morpheus83uk
Established Member
Hi Mike,
Sorry I don't understand what you mean?
Thanks
James
Sorry I don't understand what you mean?
Thanks
James
Dust Extractors
- Thread starter morpheus83uk
- Start date
Help Support UKworkshop.co.uk:
L Class ≤ 1.0% Dusts with maximum allowable concentrations (MAC) > 1 mg/m³
M Class < 0.1% Dusts with maximum allowable concentrations (MAC) ≥ 0.1 mg/m³
H Class < 0.005% Dusts with maximum allowable concentrations (MAC) < 0.1 mg/m³
Well you brought up the class system:
L Class extractors are regarded as ‘entry-level’ with M Class being the next step up. You can broadly separate them in terms of application, as follows:
L Class - for soft woods and solid surface material such as Corian.
M Class - for hard woods, board materials, concrete and brick dust.
In reality, you will find that most professional L and M Class dust extractors will have similar suction rates and filtration levels. This means the applications they can be used for are fundamentally the same. The difference will come down to features on the machine. A true M Class dust extractor will have an audible alarm to advise you when the suction rate has dropped, for example a blocked hose or full dust bag. You will generally find that when working on site, the health and safety manager will insist on using M Class dust extraction. M Class is also the minimal legal requirement, set by the HSE, so these factors alone may dictate whether you step up from L Class to M Class, when making your next purchase.
The next step up from M Class is H Class. H Class dust extractors include all the features you find with M Class units, but also offer greater suction and filtration figures, even down to the way the bag is removed from the machine to avoid particles going back into the air. H Class vacuum extractors would generally be specified if you are working in environments with highly carcinogenic dusts such as lead, carbon, tar, nickel, cobalt, copper and cadmium along with other really nasty stuff you really don’t want to be breathing in!
H Class - highly carcinogenic dusts, asbestos, formaldehyde, mould, germs and bacteria.
Now we’ve ascertained that the use of dust extraction is essential and we also know which class of extractor best suits our needs… the next question is “what other features are available and which extractor do I go for?”
Most professional and industrial dust extractors have power take-off which allows you to plug your power tool directly into the vacuum extractor, making the unit automatically turn-on when the power tool is started. This removes the need to turn-on the two items separately. There is also a delayed shut-off; when the power tool is stopped the extractor continues to run for around five seconds longer to clear both the tool and hose of any remaining particles.
But none on this has any bearing on the difference between a HVLP and a LVHP extractor, if you are sanding materials then you need a vacuum cleaner type unit, with filter bags etc, if you predominately use planing machines and the like then you need a HVLP extractor the type of filtration to either is down to what you want to achieve on air purity, you could do nothing and use an efficient air entry mask, not advisable, your clothes would be covered and you will transfer everything on your clothes with you into whatever environment you go to next.
To get back to your problem, most of the members on here have compromised their extraction systems due to various restraints put upon themselves by the amount of workshop space they have (budget should not be a factor) the LVHP vacuum cleaner type of extractor is good for dust, the higher the pressure the better, each motor is rated at Watts, but this is only half the story, the amount of stages a vacuum unit has makes it more efficient, twin motors, twin stages, a single stage unit will struggle to achieve over 150m3/hr, double the stages and you will effectively double the extract power, these units will not move large off cuts of material effectively for that you need a HVLP chip extractor, even the smallest of these will give 500m3/hr extraction at half the cost of a vacuum cleaner, but still struggle with a large volume of chips, for this type of extract it is better to overwhelm the required amount of extract power, I would advise at the very least 1500m3/hr.
Mike
Sorry guys I think I have turned into ETV.
M Class < 0.1% Dusts with maximum allowable concentrations (MAC) ≥ 0.1 mg/m³
H Class < 0.005% Dusts with maximum allowable concentrations (MAC) < 0.1 mg/m³
Well you brought up the class system:
L Class extractors are regarded as ‘entry-level’ with M Class being the next step up. You can broadly separate them in terms of application, as follows:
L Class - for soft woods and solid surface material such as Corian.
M Class - for hard woods, board materials, concrete and brick dust.
In reality, you will find that most professional L and M Class dust extractors will have similar suction rates and filtration levels. This means the applications they can be used for are fundamentally the same. The difference will come down to features on the machine. A true M Class dust extractor will have an audible alarm to advise you when the suction rate has dropped, for example a blocked hose or full dust bag. You will generally find that when working on site, the health and safety manager will insist on using M Class dust extraction. M Class is also the minimal legal requirement, set by the HSE, so these factors alone may dictate whether you step up from L Class to M Class, when making your next purchase.
The next step up from M Class is H Class. H Class dust extractors include all the features you find with M Class units, but also offer greater suction and filtration figures, even down to the way the bag is removed from the machine to avoid particles going back into the air. H Class vacuum extractors would generally be specified if you are working in environments with highly carcinogenic dusts such as lead, carbon, tar, nickel, cobalt, copper and cadmium along with other really nasty stuff you really don’t want to be breathing in!
H Class - highly carcinogenic dusts, asbestos, formaldehyde, mould, germs and bacteria.
Now we’ve ascertained that the use of dust extraction is essential and we also know which class of extractor best suits our needs… the next question is “what other features are available and which extractor do I go for?”
Most professional and industrial dust extractors have power take-off which allows you to plug your power tool directly into the vacuum extractor, making the unit automatically turn-on when the power tool is started. This removes the need to turn-on the two items separately. There is also a delayed shut-off; when the power tool is stopped the extractor continues to run for around five seconds longer to clear both the tool and hose of any remaining particles.
But none on this has any bearing on the difference between a HVLP and a LVHP extractor, if you are sanding materials then you need a vacuum cleaner type unit, with filter bags etc, if you predominately use planing machines and the like then you need a HVLP extractor the type of filtration to either is down to what you want to achieve on air purity, you could do nothing and use an efficient air entry mask, not advisable, your clothes would be covered and you will transfer everything on your clothes with you into whatever environment you go to next.
To get back to your problem, most of the members on here have compromised their extraction systems due to various restraints put upon themselves by the amount of workshop space they have (budget should not be a factor) the LVHP vacuum cleaner type of extractor is good for dust, the higher the pressure the better, each motor is rated at Watts, but this is only half the story, the amount of stages a vacuum unit has makes it more efficient, twin motors, twin stages, a single stage unit will struggle to achieve over 150m3/hr, double the stages and you will effectively double the extract power, these units will not move large off cuts of material effectively for that you need a HVLP chip extractor, even the smallest of these will give 500m3/hr extraction at half the cost of a vacuum cleaner, but still struggle with a large volume of chips, for this type of extract it is better to overwhelm the required amount of extract power, I would advise at the very least 1500m3/hr.
Mike
Sorry guys I think I have turned into ETV.
morpheus83uk
Established Member
Thank you for that it has cleared that up.
I have just looked at the extractors I linked to and yours. With the suction I presume the higher the Pa or kPa the better? And the air volume the same?
Oddly though one is measured in litres per minute and the other meters cubed per hour. Is this normal? And is there any easy comparison?
I read about M Class being used for hard wood which I will be using which is why I am looking for M Class.
As for the HVLP I presume this is high volume low pressure? And the LPHV is low pressure high volume?
And are the chip extractors mainly M Class then given their suction?
Sorry for all the questions I am just trying to get my head around it all.
Thanks
James
I have just looked at the extractors I linked to and yours. With the suction I presume the higher the Pa or kPa the better? And the air volume the same?
Oddly though one is measured in litres per minute and the other meters cubed per hour. Is this normal? And is there any easy comparison?
I read about M Class being used for hard wood which I will be using which is why I am looking for M Class.
As for the HVLP I presume this is high volume low pressure? And the LPHV is low pressure high volume?
And are the chip extractors mainly M Class then given their suction?
Sorry for all the questions I am just trying to get my head around it all.
Thanks
James
The only reason manufactures quote in anything other than m3/hr is to publish figures that seem higher, lots of conversion calculators on the web.
M class is the normal standard when using a Low pressure High volume vacuum cleaner with a few filters in it.
High Volume Low Pressure conforms to whatever filter is fitted, if you fit a pleated paper filter then you get better than class M, using the standard bag filter is not going to protect you from harmful dust.
Mike
M class is the normal standard when using a Low pressure High volume vacuum cleaner with a few filters in it.
High Volume Low Pressure conforms to whatever filter is fitted, if you fit a pleated paper filter then you get better than class M, using the standard bag filter is not going to protect you from harmful dust.
Mike
morpheus83uk
Established Member
Thanks I have found one.
I have had a look at the reviews of the ones you posted and although they aren't brilliant they all state about using them for planer thicknesses and axminsters response about moving large chips in the airflow. Would they be able to sit and effectively remove the fine dust from a random orbital sander? As this is one of the big things I would be using it for? Obviously it would cope with the table saw and router table.
Thanks
James
I have had a look at the reviews of the ones you posted and although they aren't brilliant they all state about using them for planer thicknesses and axminsters response about moving large chips in the airflow. Would they be able to sit and effectively remove the fine dust from a random orbital sander? As this is one of the big things I would be using it for? Obviously it would cope with the table saw and router table.
Thanks
James
Stepping the hose down to fit a sander will increase the pressure from the unit (Bernoulli's theorem.) and so make it more effective, however the dust capture will not be as good with just an air bag, maybe a case for a cyclone (don't believe I just said that), but do be aware that you can't use a bag in a cyclone, therefore you will expose yourself to the dust when emptying, far better to use a multi filter vacuum cleaner for that sort of extraction, my Numatic has four filters fitted to deal with dust.
Mike
Mike
morpheus83uk
Established Member
Ah so something like the Bosch would be better for sanding dust and for the bigger chips one of the ones your recommended?
Thanks
James
Thanks
James
Any type of vacuum cleaner is better for dust, its the exhaust you have to be concerned about after the air has passed through the filters, if the exhaust can be ducted to the outside that would be even better, but the quality of the filter bags and any extra filters is your first consideration.
Mike
Mike
Have a look at this: https://www.axminster.co.uk/numatic-nvd ... r-ax782721 has the option to be upgraded with a hepa filter, but also the facility to use an extra filter bag over the canister, have a look at the instructions : https://www.axminster.co.uk/media/downl ... manual.pdf page seven where its explained how to do this, although this could be done on any canister unit.
Mike
Mike
